Author: imp
Date: Wed Jun 27 23:44:37 2018
New Revision: 335753
URL: https://svnweb.freebsd.org/changeset/base/335753
Log:
Safely quote all variable expansions.
When expanding a variable set by a message from the kernel, safely
quote all arguments expanded when creating a command line for the
shell.
Reviewd by: Shawn Webb, Oliver Pinter, brd@
Sponsored by: Netflix
Modified:
head/sbin/devd/devd.cc
head/sbin/devd/devd.hh
Modified: head/sbin/devd/devd.cc
==============================================================================
--- head/sbin/devd/devd.cc Wed Jun 27 23:02:18 2018 (r335752)
+++ head/sbin/devd/devd.cc Wed Jun 27 23:44:37 2018 (r335753)
@@ -636,6 +636,30 @@ config::is_id_char(char ch) const
ch == '-'));
}
+string
+config::shell_quote(const string &s)
+{
+ string buffer;
+
+ /*
+ * Enclose the string in $' ' with escapes for ' and / characters making
+ * it one argument and ensuring the shell won't be affected by its
+ * usual list of candidates.
+ */
+ buffer.reserve(s.length() * 3 / 2);
+ buffer += '$';
+ buffer += '\'';
+ for (const char &c : s) {
+ if (c == '\'' || c == '\\') {
+ buffer += '\\';
+ }
+ buffer += c;
+ }
+ buffer += '\'';
+
+ return buffer;
+}
+
void
config::expand_one(const char *&src, string &dst)
{
@@ -650,8 +674,7 @@ config::expand_one(const char *&src, string &dst)
}
// $(foo) -> $(foo)
- // Not sure if I want to support this or not, so for now we just pass
- // it through.
+ // This is the escape hatch for passing down shell subcommands
if (*src == '(') {
dst += '$';
count = 1;
@@ -677,7 +700,7 @@ config::expand_one(const char *&src, string &dst)
do {
buffer += *src++;
} while (is_id_char(*src));
- dst.append(get_variable(buffer));
+ dst.append(shell_quote(get_variable(buffer)));
}
const string
Modified: head/sbin/devd/devd.hh
==============================================================================
--- head/sbin/devd/devd.hh Wed Jun 27 23:02:18 2018 (r335752)
+++ head/sbin/devd/devd.hh Wed Jun 27 23:44:37 2018 (r335753)
@@ -173,6 +173,7 @@ class config (protected)
void parse_one_file(const char *fn);
void parse_files_in_dir(const char *dirname);
void expand_one(const char *&src, std::string &dst);
+ std::string shell_quote(const std::string &s);
bool is_id_char(char) const;
bool chop_var(char *&buffer, char *&lhs, char *&rhs) const;
private:
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